(Meth)acrylonitriles have been manufactured in large quantities, as the intermediates for a great variety of industrial products represented by synthetic fibers and synthetic resins. As a conventional production process thereof, ammoxidation is generally known, in which olefinic starting materials, i.e., propylene, isobutene, and the like, are contacted with molecular oxygen and ammonia in the vapor phase, in the presence of a catalyst.
Whereas, with the recent rise in olefin price, development of processes for making the various derivatives which have heretofore been manufactured from olefins, using as the starting materials less expensive paraffins, comes to draw attention. As the catalyst systems used for the production of (meth)acrylonitriles from propane or isobutane by "ammoxidation" process, Sb--U oxide catalyst [Japanese Patent Publication (Kokoku) No. 14371/1972], Sb--Sn oxide catalyst (Kokoku No. 28940/1975), V--Sb oxide catalyst [Japanese Laid-open (Kokai) Nos. 33783/1972, 268668/1989, 95439/1990 and 261544/1990], Bi--Mo oxide catalyst (Kokai No. 16887/1973, Kokoku No. 42071/1980, and Kokai No. 157356/1991], V--P oxide catalyst (Kokoku No. 5188/1983), Bi--V oxide catalyst (Kokai No. 295545/1988), etc. are known. Still recently, furthermore, patent applications have been made for V--Sn--Sb--Cu oxide catalyst (Kokai No. 275266/1992), Mo--V--Te--Nb oxide catalyst (Kokai No. 257/1990), Ag--Bi--V--Mo oxide catalyst (Kokai No. 58961/1991), Ga--Bi--Mo or Ta--Bi--Mo oxide catalyst (Kokai No. 58962/1991), Mo--Ta or Mo--Nb oxide catalyst (Kokai No. 213849/1993), etc. Also mixed catalyst systems of a number of above catalyst systems with those having olefin-ammoxidation ability have been proposed (Kokai Nos. 295546/1988, 38051/1989, 17159/1990, 43949/1990, 75347/1990, 111444/1990 and 258065/1990).
Of these processes, those of adding a minor amount of a halide to the reaction systems as a promotor give the nitrites, which are the intended reaction products, at relatively high yield. However, such processes are difficult of industrial practice because of the corrosion problem of the reaction equipments which incurs restrictions on the construction materials of the equipments. On the other hand, the processes not using any promotor give only low yield of nitrites and have not reached an industrially practiceable level.